Insomniac PowerBook Problem

First post here...nice to meet everyone! Anyway, I'm at my wit's end. I've been having problems with my PowerBook sleeping for the last 2 months and I'm out of ideas. I'm relatively new to Macs, perhaps you guys have some suggestions. Here's the deal:

My PowerBook will often not sleep when I close the lid or select Sleep from the Apple menu. The display will freeze or turn off, but the hard drive will continue to spin and for all intents and purposes the computer is "on." It won't respond to any input and I must manually turn it off. The sleep indicator light will never come on. This isn't every time though. At times it will go a day or two with no issues and then the problem will crop up 3 times the next day.

Here's what I've done:
I've reset the PMU twice, I've zapped PRAM, and after no other software fixes worked, I wrote 0's to the drive and did a clean install of OS X to rule out any software problems. A bit extreme perhaps but I'm getting desperate. The only apps I run that I could see causing a software problem are Quicksilver, Adium, Desktop Manager and a Cisco VPN client for use on campus. However, I seem to have the problem whether these apps are running or not. I've talked to Apple Support and they've suggested I do the stuff I've already done. If anyone had any suggestions I would be much appreciative! I can give anyone more details if they like...

Do you have any Bluetooth devices paired with the Mac? Mouse, phone etc?
If so, are they switched to 'allow device to wake Mac'? Although this would be more likely to keep waking up the PB rather than not letting it sleep.

Did it used to work OK? And was it around the 10.3.8 update that it stopped working?

Does your latch work properly?

What did Apple support say were the options after you'd tried their suggestions?

Negative on the Bluetooth device. I've experienced the problem before 10.3.8. I got the PB in June and had no problem with sleeping until January. All of the apps I'm running now I was running well before that point. I'm just not sure whether or not to think its software or hardware. Apple Support was less than enthusiastic about me sending it in because the problem can't always be readily replicated. I'm not too keen on sending it away for a week if they aren't going to be able to reproduce the problem and then send it back not fixed.

Sounds like you have some ram in there that is out of spec. About two years ago I ram into a problem with PC2700 ram that was said to be compatible. It fit in the slots and worked fine in every other way except when I wanted it to sleep. It turned out the ram did not support the lower voltage requirements of the powerbook in the sleep mode.

What kind of ram do you have? and do you have your original ram to test out my theory?

I actually just have one 512 MB SO-DIMM stick that it was shipped with. I didn't add any third-party RAM or anything, which was actually one of the first things that Apple asked me about. I've run a few hardware diagnostic tools, all of which claimed everything was cool. If this is a software problem tho, I'm baffled...

MacRumors attracts a broad audience
of both consumers and professionals interested in
the latest technologies and products. We also boast an active community focused on
purchasing decisions and technical aspects of the iPhone, iPod, iPad, and Mac platforms.